Copper is an essential mineral for human health, but too much of it in your drinking water can cause serious problems. For millions of Americans, especially those living in homes with aging plumbing systems, copper contamination is a real concern. The Environmental Protection Agency (EPA) has established strict limits on copper in drinking water, yet copper leaches into our taps every day from corroded pipes, fixtures, and solder joints. This comprehensive guide will help you understand the risks, test your water, and take action to protect your family.
What Is Copper and Why Is It in Drinking Water?
Copper is a soft, reddish metal commonly used in plumbing systems because of its durability and antimicrobial properties. In small amounts, copper is actually necessary for bone formation, immune function, and iron metabolism in the human body. However, when copper accumulates in drinking water at elevated levels, it becomes a health hazard.
Copper enters drinking water primarily through corrosion of copper pipes, brass fixtures, and solder joints used to connect pipes in homes and buildings. Corrosion happens when water passes through the pipes and the pipe material slowly dissolves into the water. The likelihood and speed of corrosion depend on several factors including the age of the plumbing, water pH, water temperature, and the mineral composition of your water supply.
Homes built before 1990 are at highest risk because they typically have more copper piping and solder containing lead (which was banned in 1986). Even newer homes can experience copper leaching if water conditions favor corrosion. Public water systems are required to maintain corrosion control treatment, but the problem often begins inside individual homes where corrosion control is less regulated.
EPA Copper Limits and Action Levels
The EPA has set a Maximum Contaminant Level Goal (MCLG) of zero for copper, meaning the agency's ideal target is to have no copper in drinking water. However, recognizing that some copper is unavoidable in practice, the EPA established an Action Level of 1.3 milligrams per liter (mg/L). This action level is the concentration at which water systems must take corrective action.
It is important to understand the difference between the MCLG and the Action Level. The MCLG of zero represents the health-based goal. The Action Level of 1.3 mg/L is a practical trigger that requires water systems to implement treatment or corrosion control measures if more than 10 percent of tested samples exceed this concentration. This does not mean water below 1.3 mg/L is safe; it simply means the trigger for mandatory action has not been reached.
Many water quality experts recommend limiting copper exposure even below the Action Level, particularly for vulnerable populations like infants, young children, and people with certain health conditions.
Health Risks and Vulnerable Populations
Short-Term Health Effects
Acute exposure to high levels of copper in drinking water can cause gastrointestinal symptoms including nausea, vomiting, diarrhea, and abdominal cramps. These symptoms typically appear within minutes to hours of consumption and usually resolve without treatment. However, repeated or prolonged exposure to elevated copper levels can cause more serious health problems.
Long-Term Health Effects
Chronic copper exposure has been linked to several serious health conditions. Copper accumulates in the liver and kidneys, and prolonged exposure can cause liver damage, kidney problems, and other serious illnesses. Studies have shown associations between elevated copper consumption and neurological problems, particularly in children. Some research suggests that excess copper may contribute to developmental issues and learning problems in young children whose brains are still developing.
Copper in drinking water has also been investigated as a potential contributor to autoimmune conditions and other chronic diseases, though research in these areas is ongoing.
Who Is Most at Risk?
Infants and young children are at the highest risk from copper contamination. Their bodies are smaller, so the same concentration of copper represents a larger dose relative to their body weight. Additionally, their organs are still developing and may be more vulnerable to damage. The EPA recommends that infants be given water with copper levels below 1.3 mg/L, and ideally much lower.
Pregnant women should also be cautious, as excess copper may affect fetal development. People with genetic conditions affecting copper metabolism, such as Wilson's disease, must be especially careful and may need to avoid copper-contaminated water entirely.
People with liver or kidney disease may have reduced ability to process and excrete excess copper, increasing their risk of accumulation and toxicity.
How to Test Your Water for Copper
Understanding Your Water System
Before testing, determine whether you receive water from a public water system or a private well. Public water systems are required to regularly test for copper and provide results in an annual Consumer Confidence Report (also called a Water Quality Report). You can request this report from your local water utility or search for it online using your city or county name.
If you use a private well, testing is your responsibility as the property owner. The EPA does not regulate private wells, so you must arrange testing independently.
EPA-Approved Testing Methods
If your water system reports low copper levels but you are concerned about corrosion in your home's plumbing, you can conduct a simple test. The EPA recommends using the first-draw test and the flushed-sample test to identify corrosion problems in household plumbing.
First-Draw Test: Let water sit in pipes overnight (at least 6 hours), then collect the first water that comes from the tap without running it. This water has been sitting in the pipes longest and will show the highest copper levels if corrosion is occurring. This test is most useful for identifying problems in your home's plumbing.
Flushed-Sample Test: Run water for at least 30 seconds before collecting a sample. This water has not been sitting in pipes and represents the copper level in the public water supply or well water entering your home. This test shows whether the problem originates from the municipal water system or your home's plumbing.
For professional testing, hire a certified laboratory approved by your state or the EPA. Many state health departments maintain lists of approved testing labs. You can also use ClearWater's free ZIP code lookup at checkclearwater.com to find information about copper levels reported by your local water utility and connect with resources in your area.
What Copper Levels Mean
If your test results show copper levels below 1.3 mg/L, your water meets the EPA Action Level. However, this does not guarantee the water is completely safe, especially for infants and vulnerable groups. If levels are above 1.3 mg/L, your water system must take corrective action, and you should implement home-based solutions immediately.
Why Copper Leaches from Pipes
The Corrosion Process
Copper pipes do not simply fall apart; they corrode slowly as water passes through them. Corrosion is a chemical reaction between the copper metal and the water. Several factors accelerate this process:
- Low pH water: Acidic water (pH below 6.5) is more corrosive to copper pipes and fixtures than neutral water. This is why pH adjustment is a common utility treatment strategy.
- High water temperature: Hot water causes corrosion much faster than cold water. This is why copper levels are often higher in hot water than cold water.
- Chlorine and chloramine: Disinfectants used to treat municipal water can accelerate pipe corrosion in some conditions.
- Mineral content: Water that is very soft or very hard can be more corrosive than water with balanced mineral content.
- Pipe age: Older copper pipes and solder joints are more likely to corrode, especially if protective interior coatings have worn away.
This is why homes with older plumbing systems in areas with aggressive water chemistry are at highest risk for copper contamination.
Solutions to Reduce Copper in Your Drinking Water
Short-Term Solutions
Use cold water for drinking and cooking. Because hot water corrodes pipes faster, cold water typically contains less copper. Always use cold tap water for drinking, cooking, and preparing infant formula. Hot water should never be used for these purposes.
Flush your pipes in the morning. Let water run for 30 seconds to 2 minutes before collecting water for drinking or cooking. This removes water that has been sitting in pipes overnight and has had time to absorb copper.
Boiling water does not remove copper. An important point for many homeowners: boiling actually concentrates copper by removing water through evaporation. Boiling is not an effective treatment.
Point-of-Use Filtration
For homes with elevated copper levels, point-of-use filters installed directly at the kitchen sink or on the refrigerator dispenser can effectively reduce copper. Effective filter types include activated carbon filters and reverse osmosis systems. Filters must be certified to reduce copper, and you must follow the manufacturer's instructions for replacement schedules. An undersized or neglected filter can become saturated and stop removing copper effectively.
Corrosion Control Treatment (System-Level)
If testing shows that copper is leaching from your home's plumbing, work with a licensed plumber to evaluate your water conditions. For homes supplied by a public water system, your utility may need to implement stronger corrosion control treatment if copper levels are elevated across the community.
Corrosion control involves adjusting water pH to reduce the corrosive nature of the water. Most utilities adjust pH to between 7.0 and 8.5 to minimize corrosion. Some water systems also add orthophosphate, a chemical that creates a protective coating inside pipes and reduces copper leaching.
Pipe Replacement
For homes with severely corroded copper plumbing, replacing pipes with modern materials may be necessary. This is a significant investment, but it eliminates the source of the problem entirely. Modern plumbing may use copper (with better manufacturing standards), PVC, or other materials. Consult a licensed plumber to evaluate whether your pipes are candidates for replacement and what options are available.
Water Softening
In some cases, water softening systems can indirectly reduce copper leaching by adjusting the mineral balance of water. However, water softening alone may not be sufficient if pH is very low. Consult a water quality professional to determine whether softening is appropriate for your situation.
Specific Guidance for Parents and Caregivers
If you have an infant in your home, take copper contamination seriously. Infants under 6 months of age are at highest risk. If your water has tested above 1.3 mg/L copper, use bottled water for preparing infant formula and drinking water until the problem is resolved.
For children older than 6 months who are eating solid foods, the risk is lower but not eliminated. Continue using cold tap water from a flushed source, or use filtered water if your testing shows elevated copper.
Pregnant women should also take precautions and consider filtration or bottled water if copper levels are elevated, as excess copper exposure during pregnancy may affect fetal development.
Understanding Your Water Quality Report
Public water utilities are required to provide annual Consumer Confidence Reports to all customers. These reports include copper test results and information about the utility's compliance with EPA standards. Review your water quality report to see what copper levels your utility is reporting. Most reports will show whether copper met the Action Level and whether the utility has implemented corrosion control treatment.
If your utility's report shows copper at or above 1.3 mg/L, contact the utility to ask what steps they are taking to reduce copper levels. You have a right to know about water quality issues affecting your home.
You can also use ClearWater's free ZIP code lookup tool at checkclearwater.com to see copper levels and other contaminant information reported by your local water utility. This provides an easy way to understand what EPA data shows about your water supply.
Taking Action Today
If you are concerned about copper in your drinking water, start with these steps this week:
- Obtain your local water utility's Consumer Confidence Report or use ClearWater's free lookup to check reported copper levels in your area.
- Conduct a first-draw test if you suspect corrosion in your home's plumbing. Collect water that has sat overnight and have it tested at a certified laboratory.
- Begin using cold tap water for all drinking and cooking. Flush pipes for 30 seconds before collecting water.
- If you have an infant, use bottled water or filtered water until you have confirmed your tap water is safe.
- If testing shows copper above 1.3 mg/L, contact your water utility to report the problem and install a certified point-of-use filter as an interim solution.
- Consult a licensed plumber if you believe your home's plumbing is corroded and may need evaluation or replacement.
Copper contamination in drinking water is preventable and treatable. By understanding the problem, testing your water, and taking appropriate action, you can protect your family's health and ensure your drinking water is safe for everyone in your household.